Recreational vehicles have become a very popular way of traveling, especially for extended periods of time. These vehicles are equipped with a wide variety of amenities that are normally found in a residence. These include fully appointed kitchens, complete bathrooms, laundry facilities, and entertainment centers. For many years, trailers have incorporated expandable rooms, sometimes called slide-outs, to increase the interior space while parked and yet maintain legal size requirements while in motion. In the past decade, expandable rooms have become very common in motorhome applications. Owners continue to want more space and more luxurious amenities. In recent years, consumer demands have resulted in manufacturers adding multiple slide-outs to their production models, sometimes as many as four or five in a forty or forty-five foot model. The next generation motorhome, travel trailer and fifth wheel will replace the multiple slide-out modules with one or two large slide-out modules. As these modules get longer, up to 30 ft in length or more, which will replace multiple slide-outs of length that range from 8 to 12 ft, care must be taken to eliminate the twist or torsion in the chassis. In normal operation of an RV, when the vehicle is parked on an uneven surface whereby one wheel at any of the four corners of the chassis rests in a position or plane that is higher or lower than the plane defined by the point of rest of the wheels on the other three corners of the chassis, the overall chassis will then be twisted, or in engineering terms, in torsion. This twist will distort the chassis and the RV structure that is attached. This distortion will make it impossible to extend and retract the above mentioned slide-out modules with ease and reliability. A large slide-out module that is extended to enjoy the larger living space becomes a liability if the module will not retract due to the distorted or twisted chassis, which makes retraction of the slide-out module impossible. If the slide-out cannot be retracted, the RV cannot be moved, a very serious inconvenience.
The present invention, uses two (2), two-axis sensors to measure the orientation of the vehicle chassis across the width of the chassis in addition to measurements taken along the longitudinal, fore to aft axis of the chassis. Each two-axis sensor is located at opposite ends of the trailer or motorhome chassis.
The present invention is a solid state control system that may be used on any type of vehicle to insure that the chassis of the vehicle is level, or perpendicular to the pull of gravity, and in a single plane without twist or distortion. Planarization is the process of insuring that a vehicle, material or entity is in this non-distorted, planar condition.
The components of the control system include the host computer or microprocessor, the front, two-axis sensor, the rear, two-axis sensor, the user""s control panel and a remote diagnostics port for System maintenance. Each of the front and rear sensor modules includes an electronic sensor to measure level in the X direction, the measurement taken across the width of the vehicle or chassis and the Y direction, the length of the vehicle. The first priority of the host computer is to compare the X direction readings at the front and rear of the chassis. Analysis of these data will determine the amount and direction of twist in the chassis. When the magnitude and direction of twist is determined, the host computer will resolve or eliminate the twist by raising or lowering opposite corners of the chassis. When planarization is achieved, the control will then lift either side and/or either end of the chassis to achieve a level condition. The lifting means will be inflation or deflation of the airbags that are used in the vehicle""s suspension system or raising and lowering of hydraulic or electromechanical jacks located at each of the four (4) corners of the vehicle.
In addition to the host computer and the front and rear sensors, a control panel or user interface is provided for the vehicle operator. The user interface provides a pushbutton for the driver/operator to initiate the leveling sequence. In addition, a multi-line/multi character display panel or multi-color LED""s may be provide to indicate which corner of the vehicle is high or low and allows the operator to observe the System in operation. The same panel will indicate to the owner/driver/user that the vehicle is planar and conditions have been met for proper operation of the slide-out modules.